1. When two unmixable liquids like oil and vinegar are combined and then left to rest, they will naturally separate and form distinct...
- A. solutions.
- B. layers.
- C. compounds.
- D. crystals.
2. The tendency of a liquid to mix with another liquid is an example of one of its physical...
- A. properties.
- B. reactions.
- C. temperatures.
- D. volumes.
3. Which of the following pairs of substances would most likely behave like oil and vinegar when you try to mix them?
- A. Water and food coloring
- B. Milk and chocolate syrup
- C. Melted butter and water
- D. Water and sugar
4. What term best describes liquids like water and milk, which combine easily to form a uniform mixture?
- A. Layered
- B. Unmixable
- C. Mixable
- D. Separated
5. What is the primary reason that some liquids, like oil and water, are considered "unmixable"?
- A. The oil is always heavier than the water.
- B. They are composed of very different types of molecules that do not attract each other.
- C. One liquid is a much brighter color than the other.
- D. The container they are in is not shaken hard enough to force them to combine.
6. What is the primary reason that water and oil separate into layers after being vigorously shaken together?
- A. The difference in density is the only factor, causing the lighter oil to float regardless of any molecular forces.
- B. Oil molecules are naturally repelled by the sides of any container, forcing them into a separate layer.
- C. Water molecules are more attracted to each other than to oil molecules.
- D. A slow chemical reaction occurs that builds a solid wall between the two liquids.
7. The text uses an analogy of "groups of friends" to explain molecular behavior. In this analogy, the separation of oil and water is like...
- A. all the friends deciding to sit together at one big table.
- B. two groups of friends choosing to sit at separate tables.
- C. one group of friends getting into an argument and leaving the lunchroom entirely.
- D. the friends from different groups deciding to trade lunches with each other.
8. When a student pours vegetable oil into a glass of water, the oil fails to mix in. Why does this happen on a molecular level?
- A. The oil is too thick.
- B. The water molecules stick together tightly.
- C. The oil molecules are much larger than the water molecules.
- D. The water is not hot enough to dissolve the oil.
9. Salad dressing often separates into an oily layer and a watery layer. Why is it necessary to shake the bottle before use?
- A. Shaking activates the flavor molecules, making the dressing taste stronger.
- B. The motion helps to permanently fuse the oil and water molecules together.
- C. It temporarily forces the separate liquid layers to disperse into each other.
- D. Shaking is required to cool the dressing down to the proper serving temperature.
10. The strong attraction that water molecules have for other water molecules is an example of which force?
- A. Chemical repulsion
- B. Gravitational pull
- C. Molecular cohesion
- D. Electrical insulation